The development of biological test systems to meet the future requirements of biomedical research is of necessity long term and resource intensive. An integral part of the management of the National Institutes of Health Genetics Resource (NIHGR) has been the formation of new animal models and since its inception about 10 years ago, approximately 75 new models have been developed utilizing the internal resources of the NIHGR. These models which are designed to support clinical research are developed in close conjunction with the clinical investigator. Areas in which models have been or are being developed, include immunology, infectious diseases, behavior, neurology, diabetes mellitus, cardiovascular diseases to include hypertension, cerebral and myocardial infarcts and metabolic diseases.